Multi-bar linkage mechanism based conveyor

ABSTRACT

The invention discloses a multi-bar linkage mechanism based conveyor, comprising a gantry system, a multi-bar linkage mechanism based conveyor boom, a boom support, a two-drum winch, a roller unit and an automatic control system. The gantry system, the two-drum winch and the boom support are mounted on a deck of a hull. The conveyor boom is formed of multi-bar linkage mechanisms, the movement of which can be changed. Rollers are mounted on the conveyor boom. The rear segment of the conveyor boom is articulated with the boom support. The two-drum winch is connected to the multi-bar linkage mechanism based conveyor boom via a steel wire rope and by a set of gantry pulleys. A hydraulic device and a control device are arranged between adjacent multi-bar linkage mechanisms. A tension sensor is arranged at an end of the steel wire rope. The whole conveyor is controlled by the automatic control system.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Patent Application No. PCT/CN2019/079653, filed on Mar. 26, 2019, which claims the benefit of priority from Chinese Patent Application No. 201810274933.8, filed on Mar. 30, 2018. The contents of the aforementioned application, including any intervening amendments thereto, are incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present invention relates to the technical field of conveyors for transport ships and in particular to a multi-bar linkage mechanism based conveyor.

BACKGROUND OF THE PRESENT INVENTION

In recent years, inland sand unloading vessels have attracted widespread attention due to their advantages of flexible and quick cargo unloading performance. However, the instability of such vessels also has become increasingly prominent. Furthermore, due to large water coverage and rich waterway resources in China, inland sand unloading vessels have been widely applied and this industry is booming. However, the conveyor boom of a conventional self-unloading vessel may have a length up to 40 m, but it cannot be retracted, resulting in low stability and high safety hazard. For example, since accidents frequently occur in the conventional overhung belt racks, the insurance for belt racks had been refused by insurance companies in China.

Therefore, to solve the technical difficulty in retracting conveyor booms, many solutions have been proposed in China, such as stretchable and retractable conveyor booms, rotary conveyor booms and folding conveyor booms.

The published Inventive Patent No. 201610594201.8, entitled “SELF-ADAPTIVE INTEGRALLY-OVERTURNED CONVEYOR”, provided a conveying solution in which a two-drum winch and an integral trussed boom are used and the conveyor boom is pulled by the two-drum winch to be folded. This solution solves occupation of the space of the hull to some extent; the integral overturning mode is simpler and more convenient than the folded overturning mode; and during the sand unloading, the boom is higher in safety. However, due to the use of the integral trussed boom that is fixed in length, the conveying distance is not adjustable. Although the integral overturning mode is simpler and more convenient than the folded overturning mode, the overturned conveyor arm is suspended, not firmly fixed, resulting in high safety hazard.

The published Inventive Patent No. 201610728114.7, entitled “CONVEYOR WITH STRETCHABLE AND RETRACTABLE CONVEYOR ARM”, provided a solution in which a multi-stage hydraulic cylinder and a scissor fork mechanism are used, and the retraction of the scissor fork mechanism is realized by the multi-stage hydraulic cylinder to thus make the conveyor arm stretchable and retractable. This solution realizes, to some extent, small influence to the balance of the hull by the stretch and retraction of the conveyor arm, large stretchable distance, high stretch and retraction efficiency, stable operation, and high safety. In contrast, compared with the scissor fork mechanism, the multi-bar linkage mechanism is more stable in operation, larger in the stretchable distance, and safer than the multi-stage hydraulic cylinder because the conveyor boom is unfolded in a unit of multi-bar linkage mechanisms; no tensioning mechanism is required; and it is more convenient for production and assembly.

SUMMARY OF THE PRESENT INVENTION

An objective of the present invention is to provide a multi-bar linkage mechanism based conveyor, to solve problems of self-unloading vessels such as large footprint in an out-of-service state and complex retraction operation, and problems in the prior art such as complex gantry structure, overweight conveyor boom, insufficient length of the conveyor arm, complex mounting and debugging, lack of automatic control, lack of safety guard device, etc., in order to reduce the manufacture and maintenance cost and improve the automation and safety.

To solve those technical problems, the present invention provides a multi-bar linkage mechanism based conveyor, comprising a gantry system 1, a gantry, a set of gantry pulleys, gantry pulleys, a gantry support, a multi-bar linkage mechanism based conveyor boom 2, a boom support 3, a first two-drum winch 4, a roller unit 5, a second two-drum winch 6, a hull 7 and an automatic control system. The multi-bar linkage mechanism based conveyor boom 2 comprises multi-bar linkage mechanisms 201 and hydraulic cylinders 202, and is in a composite structure of carbon fibers and carbon steel. The multi-bar linkage mechanism based conveyor boom 2 is articulated with the boom support 3 to facilitate adjustment of the conveying angle of the multi-bar linkage mechanism based conveyor boom 2. The multi-bar linkage mechanism based conveyor boom 2 comprises a plurality of multi-bar linkage mechanisms 201 each having a set of pulleys 203, and each two adjacent multi-bar linkage mechanisms 201 are powered by one hydraulic cylinder 202. To retract the multi-bar linkage mechanism based conveyor boom 2, the adjacent multi-bar linkage mechanisms 201 are stretched or retracted one by one, and each two adjacent multi-bar linkage mechanisms 201 are driven by one hydraulic cylinder 202. Thus, the conveyor boom moves. As the movement principle of the multi-bar linkage mechanisms 201, the multi-bar linkage mechanism 201 comprises, on a single side, eight bars among which: a first bar 11 is fixed, the second bar 12 is pushed by a hydraulic cylinder 202, the fourth bar 14 is driven by the second bar 12 so that the

-   -   third bar 13 moves together, and the fifth bar 15 is driven by         the second bar 12 and the third bar 13 so that the seventh bar         17 and the sixth bar 16 that is directly articulated with the         second bar 12 move together, and in this way, the eighth bar 18         is driven to move horizontally. Accordingly, the multi-bar         linkage mechanism based conveyor boom 2 can be stretched         smoothly.     -   The multi-bar linkage mechanism based conveyor boom 2 comprises         multi-bar linkage mechanisms 201, hydraulic cylinders 202 and         pulleys 203. The first two-drum winch 4 is connected to the         pulleys 203 on the multi-bar linkage mechanism based conveyor         boom 2 via a steel wire rope and by a set of gantry pulleys 101         arranged on top of the gantry. A tension sensor 19 is arranged         at an end of the steel wire rope. When tension information         obtained by the tension sensor 19 indicates a risk value, the         whole conveyor may be controlled by the automatic control system         to stop operating. The second two-drum winch 6 is connected to a         gantry pulley 102 arranged at an upper end of the gantry via a         steel wire rope. A tension sensor 19 is arranged at an end of         the steel wire rope. The stability of the whole gantry system 1         is determined through the tension sensor 19, to avoid the loss         of stability of the whole system. Both an angle of pulling of         the whole conveyor and the stability of the gantry system 1 are         controlled by the automatic control system, by analyzing the         information from the tension sensor 19. In this way, the         automatic control and the safety monitoring are realized. Each         multi-bar linkage mechanism 201, serving as an operating unit,         of the multi-bar linkage mechanism based conveyor boom 2 can         send a signal to a corresponding hydraulic cylinder 202 by the         control system, to determine the stretch distance of the         multi-bar linkage mechanism based conveyor boom 2, thus to         stretch the multi-bar linkage mechanisms 201 one by one.     -   In the gantry system 1, the set of gantry pulleys comprises a         set of front pulleys that are connected to the pulleys 203 on         the multi-bar linkage mechanism based conveyor boom 2 via a         steel wire rope, and a set of rear pulleys that are connected to         the first two-drum winch 4 via a steel wire rope. The second         two-drum winch 6 is connected to a gantry pulley 102 arranged at         an upper end of the gantry via a steel wire rope. The gantry is         connected to the multi-bar linkage mechanism based conveyor boom         2 via a steel wire rope, and the gantry and the multi-bar         linkage mechanism based conveyor boom 2 together form a stable         and substantially triangular structure. The gantry is         articulated to a gantry support and is able to rotate around the         gantry support by a certain angle. The multi-bar linkage         mechanism based conveyor boom 2 is articulated with the boom         support 3. In the gantry system 1, the steel wire ropes         separately connected to the first two-drum winch 4 and the         second two-drum winch 6 are each equipped with a tension sensor         19, information from a respective tension sensor 19 is         transmitted to the automatic control system by the stretch         distance of the multi-bar linkage mechanism based conveyor boom         2, and then the starting/stopping of the first two-drum winch 4,         the second two-drum winch 6 and the hydraulic cylinder 202 is         controlled by the automatic control system according to the         safety range of this tension. The gantry system 1, the boom         support 3, the first two-drum winch 4 and the second two-drum         winch 6 are all mounted on a deck of a hull 7. The gantry can be         pulled by the steel wire rope to rotate, by controlling the         second two-drum winch 6 to start or stop, so that the multi-bar         linkage mechanism based conveyor boom 2 can rotate by an angle         ranging from −20° to +20°.     -   The roller unit 5 comprises upper bearing rollers 8, lower         return rollers 9 and reversing rollers 10. The upper bearing         rollers 8 are uniformly mounted on the cross-bar on the surface         of the boom. The lower return rollers 9 are mounted on the         cross-bar on the bottom of the boom. The reversing rollers 10         are mounted at a forefront end of the multi-bar linkage         mechanism based conveyor boom 2. Automatic tensioning can be         realized since the multi-bar linkage mechanisms 201 of the         multi-bar linkage mechanism based conveyor boom 2 are stretched.         No tensioning device is required, so that the overall structure         is more concise.     -   The multi-bar linkage mechanism based conveyor boom 2 is simple         in structure. Each multi-bar linkage mechanism 201 is connected         by a bolt. By obtaining stressed deformation information of each         multi-bar linkage mechanism 201 from the tension sensor 19 by         using the automatic control system, the multi-bar linkage         mechanism based conveyor boom 2 is controlled and monitored         precisely. Accordingly, risk factors can be found in time. This         can reduce the fault probability and ensure the operating         efficiency of the conveyor because the operators can carry out         repairs in advance. Furthermore, the whole conveyor is         automatically controlled by a programmable control system.     -   Compared with the prior art, the multi-bar linkage mechanism         based conveyor designed according to the above technical         solution has the following beneficial effects. Compared with the         integral trussed boom and the scissor fork mechanism used in the         prior art, the multi-bar linkage mechanism based conveyor boom 2         has the following advantages: first, the overall structure is         simple and the structural modularization is convenient for         production and assembly; second, the deformation under load is         low;     -   third, the conveying length is increased; and fourth, high         safety and better stretch and retraction performance are         provided. Since a tension sensor 19 is arranged at an end of the         steel wire rope, when the multi-bar linkage mechanism based         conveyor boom 2 is to be retracted, automatic control can be         realized by the automatic control system. The operating         difficulty of the operators is greatly decreased, and the safety         in operating the device is significantly improved. The multi-bar         linkage mechanism based conveyor boom 2 will not occupy the         space of the hull 7. The multi-bar linkage mechanism based         conveyor boom 2 is in a composite structure of carbon fibers and         common carbon steel. The connection of the multi-bar linkage         mechanisms in units and by a set of bolts is convenient for         transportation and detachment. This greatly reduces the weight         of the multi-bar linkage mechanism based conveyor boom 2 and         enhances the controllability of the multi-bar linkage mechanism         based conveyor boom 2. Due to the multi-bar linkage mechanisms         201, the torsional strength and the stability of the conveyor         are improved. This greatly increases the length of the multi-bar         linkage mechanism based conveyor boom 2 and greatly increases         the conveying range. In the multi-bar linkage mechanism based         conveyor, by changing the retraction of the conveyor boom to         horizontal retraction, the operation is simpler and more         convenient than the integral overturning mode and the folded         overturning mode; and during the sand unloading, the boom is         higher in safety. Furthermore, no tensioning device is required.         This reduces loads on the boom. Moreover, it is easy to realize         automatic adjustment of the tension and deviation of the         conveyor belt, high retraction efficiency, more reliable safety         factor, low maintenance and use costs, etc.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an overall structure diagram of a multi-bar linkage mechanism based conveyor;

FIG. 2 is a partial structure diagram of a multi-bar linkage mechanism based conveyor boom;

FIG. 3 is a structure diagram of a multi-bar linkage mechanism; and

FIG. 4 is a schematic view of a multi-bar linkage mechanism based conveyor, in the retracted state, in which:

-   -   1: gantry system;     -   101: gantry pulley arranged on top of the gantry;     -   102: gantry pulley arranged at an upper end of the gantry     -   2: multi-bar linkage mechanism based conveyor boom;     -   201: multi-bar linkage mechanism;     -   202: hydraulic cylinder;     -   203: pulley;     -   231: pulley sheave;     -   232: connecting rod;     -   3: boom support;     -   4: first two-drum winch;     -   5: roller unit;     -   6: second two-drum winch;     -   7: hull;     -   8: upper bearing roller;     -   9: lower return roller;     -   901: connection handle;     -   10: reversing roller;     -   11: first bar;     -   12: second bar;     -   13: third bar;     -   14: fourth bar;     -   15: fifth bar;     -   16: sixth bar;     -   17: seventh bar;     -   18: eighth bar; and     -   19: tension sensor.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The present invention will be further described below with reference to the accompanying drawings by specific embodiments.

As shown in FIG. 1, in the gantry system 1, the set of gantry pulleys comprises a set of front pulleys that are connected to the multi-bar linkage mechanism based conveyor boom 2 via a steel wire rope, and a set of rear pulleys that are connected to the first two-drum winch 4 via a steel wire rope. The second two-drum winch 6 is connected to a gantry pulley 102 arranged at an upper end of the gantry via a steel wire rope. The gantry is connected to set of pulleys 203 on the multi-bar linkage mechanism 201 based conveyor boom 2 via a steel wire rope, and the gantry and the multi-bar linkage mechanism based conveyor boom 2 together form a stable and substantially triangular structure. The gantry is articulated to a gantry support and is able to rotate around the gantry support by a certain angle. The multi-bar linkage mechanism based conveyor boom 2 is articulated with the boom support 3. In the gantry system 1, the steel wire ropes separately connected to the first two-drum winch 4 and the second two-drum winch 6 are each equipped with a tension sensor 19, information from a respective tension sensor 19 is transmitted to the automatic control system by the stretch distance of the multi-bar linkage mechanism based conveyor boom 2, and then the starting/stopping of the first two-drum winch 4, the second two-drum winch 6 and the hydraulic cylinder 202 is controlled by the automatic control system according to the safety range of this tension. The gantry system 1, the boom support 3, the first two-drum winch 4 and the second two-drum winch 6 are all mounted on a deck of a hull 7. The gantry can be pulled by the steel wire rope to rotate, by controlling the second two-drum winch 6 to start or stop, so that the multi-bar linkage mechanism based conveyor boom 2 can rotate by an angle ranging from −20° to +20°.

As shown in FIG. 2, the multi-bar linkage mechanism based conveyor boom 2 comprises multi-bar linkage mechanisms 201 and hydraulic cylinders 202. Each two adjacent multi-bar linkage mechanisms 201 are powered by one hydraulic cylinder 202. To retract the multi-bar linkage mechanism based conveyor boom 2, the adjacent multi-bar linkage mechanisms 201 are stretched or retracted one by one. The first two-drum winch 4 is connected to the pulleys 203 on the multi-bar linkage mechanism based conveyor boom 2 via a steel wire rope and by a set of gantry pulleys 101 arranged on top of the gantry. A tension sensor 19 is arranged at an end of the steel wire rope. The pulling of the whole conveyor is controlled by the automatic control system. The second two-drum winch 6 is connected to a gantry pulley 102 arranged at an upper end of the gantry via a steel wire rope. A tension sensor 19 is arranged at an end of the steel wire rope. The stability of the whole gantry system 1 is determined through the tension sensor 19. Both an angle of pulling of the whole conveyor and the stability of the gantry system 1 are controlled by the automatic control system. Each multi-bar linkage mechanism 201, serving as an operating unit, of the multi-bar linkage mechanism based conveyor boom 2 can send a signal to a hydraulic cylinder 202 by the control system, to determine the stretch distance of the multi-bar linkage mechanism based conveyor boom 2. The roller unit 5 comprises upper bearing rollers 8, lower return rollers 9 and reversing rollers 10. The upper bearing rollers 8 are uniformly mounted on the cross-bar on the surface of the boom. The lower return rollers 9 are mounted on the cross-bar on the bottom of the boom. The reversing rollers 10 are mounted at a forefront end of the conveyor boom 2. Automatic tensioning can be realized since the multi-bar linkage mechanisms 201 of the multi-bar linkage mechanism based conveyor boom 2 are stretched. No tensioning device is required, so that the overall structure is more concise.

With reference to FIG. 3, the multi-bar linkage mechanism 201 comprises, on a single side, eight bars among which: a first bar 11 is fixed, two ends of a second bar 12 are articulated with the first bar 11, a fifth bar 15 and a sixth bar 16, the second bar 12 is articulated with a fourth bar 14 at a position that is 43%-44% of its whole length, two ends of a third bar 13 are articulated with the first bar 11, the fourth bar 14 and a seventh bar 17, two ends of the seventh bar 17 are articulated with the third bar 13, the fourth bar 14 and an eighth bar 18, the seventh bar 17 is articulated with the fifth bar 15 at a position that is 56%-57% of its whole length, two ends of the sixth bar 16 are articulated with the second bar 12, the fifth bar 15 and the eighth bar 18, and the eighth bar 18 can move. To realize the movement of the eighth bar 18, the second bar 12 is pushed by a hydraulic cylinder 202, the fourth bar 14 is driven by the second bar 12 so that the third bar 13 moves together, and the fifth bar 15 is driven by the second bar 12 and the third bar 13 so that the seventh bar 17 and the sixth bar 16 that is directly articulated with the second bar 12 move together, and in this way, the eighth bar 18 is driven to move horizontally.

In another embodiment of the present invention, the multi-bar linkage mechanism based conveyor boom 2 may be completely in a structure of common carbon steel.

In another embodiment of the present invention, the set of pulleys on the multi-bar linkage mechanism based conveyor boom 2 may include an even number of sets of pulleys of various types, which are dispersed one before the other.

The embodiment of the present invention has the following operating principle. The multi-bar linkage mechanism based conveyor boom 2 is stretched by the hydraulic system in each multi-bar linkage mechanism 201, simultaneously the first two-drum winch 4 and the second two-drum winch 6 are started to tension the steel wire rope, the steel wire rope for the set of pulleys on the gantry is tensioned to a set pre-tensioning force, the hydraulic cylinder 202 reaches a set position, and the hydraulic cylinder 202, the first two-drum winch 4 and the second two-drum winch 6 all automatically stop operating. The gantry is pulled by the second two-drum winch 6 by a steel wire rope, and the gantry and the multi-bar linkage mechanism based conveyor boom 2 together form a stable and substantially triangular structure. In this way, a stable structure is formed. Therefore, the conveying angle of the multi-bar linkage mechanism based conveyor boom 2 can be adjusted by pulling the gantry by the second two-drum winch 6. During the sand unloading, the second two-drum winch 6 may play a role of fixing the conveyor by the steel wire rope. The steel wire ropes connected to the first two-drum winch 4 and the second two-drum winch 6 are each equipped, at an end thereof, with a tension sensor 19. When the tension becomes abnormal or when the multi-bar linkage mechanism based conveyor boom 2 runs under overloads, the tension sensor 19 on the steel wire rope will give an alarm and send a stop signal to the control system, so as to ensure the safety operation of the conveyor. The present invention is not limited to the above implementations. All multi-bar conveyors obtained by using the same structures as or similar structures to those described in the above embodiments of the present invention shall be within the protection scope of the present invention. 

What is claimed is:
 1. A multi-bar linkage mechanism based conveyor, comprising a gantry system (1), a multi-bar linkage mechanism based conveyor boom (2), a boom support (3), a first two-drum winch (4), a roller unit (5), a second two-drum winch (6), an automatic control system and a hull (7), wherein the gantry system (1) comprises a gantry, a set of gantry pulleys and a gantry support; wherein the multi-bar linkage mechanism based conveyor boom (2) comprises multi-bar linkage mechanisms (201), hydraulic cylinders (202) and pulleys (203), and is in a composite structure of carbon fibers and carbon steel; the multi-bar linkage mechanism based conveyor boom (2) is articulated with the boom support (3), the multi-bar linkage mechanism based conveyor boom (2) comprises a plurality of multi-bar linkage mechanisms (201) each having a set of pulleys (203), and each two adjacent multi-bar linkage mechanisms (201) are powered by one hydraulic cylinder (202); the multi-bar linkage mechanism (201) comprises, on a single side, eight bars among which: a first bar (11) is fixed and the first bars (11) on two opposite sides form a boom, two ends of a second bar (12) are articulated with the first bar (11), a fifth bar (15) and a sixth bar (16), the second bar (12) is articulated with a fourth bar (14) at a position that is 43%-44% of its whole length, two ends of a third bar (13) are articulated with the first bar (11), the fourth bar (14) and a seventh bar (17), two ends of the seventh bar (17) are articulated with the third bar (13), the fourth bar (14) and an eighth bar (18), the seventh bar (17) is articulated with the fifth bar (15) at a position that is 56%-57% of its whole length, two ends of the sixth bar (16) are articulated with the second bar (12), the fifth bar (15) and the eighth bar (18), and the eighth bar (18) can move; to realize the movement of the eighth bar (18), the second bar (12) is pushed by a hydraulic cylinder (202), the fourth bar (14) is driven by the second bar (12) so that the third bar (13) moves together, and the fifth bar (15) is driven by the second bar (12) and the third bar (13) so that the seventh bar (17) and the sixth bar (16) that is directly articulated with the second bar (12) can move together, and in this way, the eighth bar (18) is driven to move horizontally; the first two-drum winch (4) is connected to the pulleys (203) on the multi-bar linkage mechanism based conveyor boom (2) via a steel wire rope and by a set of gantry pulleys (101) arranged on top of the gantry, a tension sensor (19) is arranged at an end of the steel wire rope, and the pulling of the whole conveyor is controlled by the automatic control system; the second two-drum winch (6) is connected to a gantry pulley (102) arranged at an upper end of the gantry via a steel wire rope, a tension sensor (19) is arranged at an end of the steel wire rope, and an angle of pulling of the whole conveyor and the stability of the gantry system (1) are controlled by the automatic control system; each multi-bar linkage mechanism (201), serving as an operating unit, of the multi-bar linkage mechanism based conveyor boom (2) can send a signal to a hydraulic cylinder (202) by the control system, so as to control the stretch distance of the multi-bar linkage mechanism based conveyor boom (2); the roller unit (5) comprises upper bearing rollers (8) and lower return rollers (9); an upper cross-bar and a lower cross-bar are mounted on the first bar (11) of each multi-bar linkage mechanism (201), an upper mounting rack is arranged above the upper cross-bar and on an inner side of the first bar (11), a first upper bearing roller, a second upper bearing roller and a third upper bearing roller which are connected to each other are arranged at an inside upper end of the upper mounting rack, and the first and third upper bearing rollers are arranged obliquely; a connection handle (901) is connected above two ends of the lower cross-bar, the connection handle (901) can rotate relatively to the lower cross-bar, and the lower return rollers are arranged on the connection handle (901); a carrier is arranged on the first bar (11) at a position above the upper cross-bar, the hydraulic cylinder (202) is arranged above the carrier, the hydraulic cylinder (202) comprises a cylinder and a piston, and the second bar (12) is connected above the piston; the pulley (203) is also connected above the second bar (12), the pulley (203) comprises a pulley sheave (231) and a connecting rod (232) by which the pulley sheave (231) is connected above the second bar (12); a dual-purpose hole is formed in the middle of the boom support (3), which saves material in light load situations and into which reinforced columns are inserted in heavy load situations; and in each two adjacent multi-bar linkage mechanisms (201), the second bar (12) of a multi-bar linkage mechanism with a hydraulic cylinder (202) is connected to the sixth bar (16) of a multi-bar linkage mechanism (201) without a hydraulic cylinder (202) to transfer power.
 2. The multi-bar linkage mechanism based conveyor according to claim 1, wherein the set of gantry pulleys corresponding to the gantry system (1) comprises a set of front pulleys that are connected to the pulleys (203) on the multi-bar linkage mechanism based conveyor boom (2) via a steel wire rope, and a set of rear pulleys that are connected to the first two-drum winch (4) via a steel wire rope; and the gantry is connected to the multi-bar linkage mechanism based conveyor boom (2) via a steel wire rope, and the gantry and the multi-bar linkage mechanism based conveyor boom (2) together form a stable and substantially triangular structure, and the gantry is articulated to a gantry support and is able to rotate around the gantry support by a certain angle.
 3. The multi-bar linkage mechanism based conveyor according to claim 1, wherein the multi-bar linkage mechanism based conveyor boom (2) is articulated with the boom support (3); the gantry system (1), the boom support (3), the first two-drum winch (4) and the second two-drum winch (6) are all mounted on a deck of a hull (7); and, by the second two-drum winch (6), the multi-bar linkage mechanism based conveyor boom (2) can rotate by an angle ranging from −20° to +20° by pulling the gantry to rotate by a steel wire rope.
 4. The multi-bar linkage mechanism based conveyor according to claim 2, wherein the multi-bar linkage mechanism based conveyor boom (2) is articulated with the boom support (3); the gantry system (1), the boom support (3), the first two-drum winch (4) and the second two-drum winch (6) are all mounted on a deck of a hull (7); and, by the second two-drum winch (6), the multi-bar linkage mechanism based conveyor boom (2) can rotate by an angle ranging from −20° to +20° by pulling the gantry to rotate by a steel wire rope.
 5. The multi-bar linkage mechanism based conveyor according to claim 1, wherein, in the gantry system (1), the steel wire ropes separately connected to the first two-drum winch (4) and the second two-drum winch (6) are each equipped with a tension sensor (19), information from a respective tension sensor (19) is transmitted to the automatic control system by the stretch distance of the multi-bar linkage mechanism based conveyor boom (2), and then the starting/stopping of the first two-drum winch (4), the second two-drum winch (6) and the hydraulic cylinder (202) is controlled by the automatic control system according to the safety range of this tension.
 6. The multi-bar linkage mechanism based conveyor according to claim 1, wherein the roller unit (5) further comprises reversing rollers (10) that are mounted at a forefront end of the multi-bar linkage mechanism based conveyor boom (2), and automatic tensioning can be realized since the multi-bar linkage mechanisms (201) of the multi-bar linkage mechanism based conveyor boom (2) are stretched.
 7. The multi-bar linkage mechanism based conveyor according to claim 1, wherein each multi-bar linkage mechanism (201) of the multi-bar linkage mechanism based conveyor boom (2) is connected by a bolt, and the conveyor is automatically controlled by a programmable control system. 